The present invention is a fiber optic product designed for monitoring the health of a building and, more particularly, for the early detection of unwanted changes in moisture and temperature that are commonly associated with roof leaks. According to construction industry publications, approximately 70% of construction litigation costs involve the roof system. Further, it is commonly asserted that up to 75% of all new roof systems leak within the first five years. Early and reliable roof leak detection is therefore a problem of paramount importance for building monitoring and maintenance.
The problem of detection of leaks in roofs is primarily addressed today via three methods:                1. Thermograph imaging: Specialized equipment using thermographic imaging (heat imaging via thermal imaging cameras) to discover relative leak location after water penetration has been reported.        2. Vector Field Mapping (VFM): Electric charge through a wire buried below the membrane of the roof. The presence of water causes a variation in electrical impedance.        3. Nuclear scan: Utilizing a radioactive isotope device and specialized personnel to determine the presence of water by changes in radiation levels.Of these methods, only the VFM method provides any early roof leak detection capability. However, VFM tends to have a high rate of false detection when used for early roof leak detection. That is, the impedance levels of the inductive or capacitive reactance between wires can change even if water has not leaked through the roofing membrane. In addition, none of these methods provide a means for detecting intrusion or changes in strain associated with excessive load. Additionally, none provide a means of assurance of insulation and reflective performance of roofs.        
With regards to fiber optic sensing, Brillouin, Raman, and interferometer applications are well known and widely deployed; however, none have been suitable for roof applications. This is because existing optical sensing technologies do not provide a means for directing and maintaining moisture at or near the sensing fiber optic strand. Moreover, existing installation practices of sensing fiber optic strands for strain measurements is difficult and labor intensive. Because of installation difficulty, installation costs and lack of assurance of detection of intrusive events (water, temperature, and strain), sensing fibers have not been utilized in roof construction. As a result, there is a continuing need for improved building monitoring systems for detecting roof leaks.